#!/usr/bin/env python
#
# Copyright (C) 2016 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import aiohttp
import asyncio
import json
from pkg_resources import parse_version

from ..controller.controller_error import ControllerError
from ..config import Config
from ..version import __version__


import logging
log = logging.getLogger(__name__)


class HypervisorError(ControllerError):
    pass


class Hypervisor:
    """
    A GNS3 hypervisor.
    """

    def __init__(self, hypervisor_id, protocol="http", host="localhost", port=8000, user=None, password=None):
        log.info("Create hypervisor %s", hypervisor_id)
        self._id = hypervisor_id
        self._protocol = protocol
        self._host = host
        self._port = port
        self._user = None
        self._password = None
        self._setAuth(user, password)
        self._connected = False
        # The remote hypervisor version
        # TODO: For the moment it's fake we return the controller version
        self._version = __version__

        # If the hypervisor is local but the hypervisor id is local
        # it's a configuration issue
        if hypervisor_id == "local" and Config.instance().get_section_config("Server")["local"] is False:
            raise HypervisorError("The local hypervisor is started without --local")

    def _setAuth(self, user, password):
        """
        Set authentication parameters
        """
        self._user = user
        self._password = password
        if self._user and self._password:
            self._auth = aiohttp.BasicAuth(self._user, self._password)
        else:
            self._auth = None

    @property
    def id(self):
        """
        :returns: Hypervisor identifier (string)
        """
        return self._id

    @property
    def host(self):
        """
        :returns: Hypervisor host (string)
        """
        return self._host

    @property
    def user(self):
        return self._user

    @user.setter
    def user(self, value):
        self._setAuth(value, self._password)

    @property
    def password(self):
        return self._password

    @user.setter
    def password(self, value):
        self._setAuth(self._user, value)

    def __json__(self):
        return {
            "hypervisor_id": self._id,
            "protocol": self._protocol,
            "host": self._host,
            "port": self._port,
            "user": self._user,
            "connected": self._connected
        }

    @asyncio.coroutine
    def httpQuery(self, method, path, data=None):
        if not self._connected:
            response = yield from self._runHttpQuery("GET", "/version")
            if "version" not in response.json:
                raise aiohttp.web.HTTPConflict(text="The server {} is not a GNS3 server".format(self._id))
            if parse_version(__version__)[:2] != parse_version(response.json["version"])[:2]:
                raise aiohttp.web.HTTPConflict(text="The server {} versions are not compatible {} != {}".format(self._id, __version__, response.json["version"]))

        self._connected = True
        return (yield from self._runHttpQuery(method, path, data=data))

    @asyncio.coroutine
    def _runHttpQuery(self, method, path, data=None):
        with aiohttp.Timeout(10):
            with aiohttp.ClientSession() as session:
                url = "{}://{}:{}/v2/hypervisor{}".format(self._protocol, self._host, self._port, path)
                headers = {'content-type': 'application/json'}
                if data:
                    if hasattr(data, '__json__'):
                        data = data.__json__()
                    data = json.dumps(data)
                response = yield from session.request(method, url, headers=headers, data=data, auth=self._auth)
                body = yield from response.read()
                if body:
                    body = body.decode()

                if response.status >= 300:
                    if response.status == 400:
                        raise aiohttp.web.HTTPBadRequest(text="Bad request {} {}".format(url, body))
                    elif response.status == 401:
                        raise aiohttp.web.HTTPUnauthorized(text="Invalid authentication for hypervisor {}".format(self.id))
                    elif response.status == 403:
                        raise aiohttp.web.HTTPForbidden(text="Forbidden {} {}".format(url, body))
                    elif response.status == 404:
                        raise aiohttp.web.HTTPNotFound(text="{} not found on hypervisor".format(url))
                    elif response.status == 409:
                        raise aiohttp.web.HTTPConflict(text="Conflict {} {}".format(url, body))
                    else:
                        raise NotImplemented("{} status code is not supported".format(e.status))
                if body and len(body):
                    try:
                        response.json = json.loads(body)
                    except json.JSONDecodeError:
                        raise aiohttp.web.HTTPConflict(text="The server {} is not a GNS3 server".format(self._id))
                if response.json is None:
                    response.json = {}
                return response

    @asyncio.coroutine
    def post(self, path, data={}):
        return (yield from self.httpQuery("POST", path, data))

    @asyncio.coroutine
    def delete(self, path):
        return (yield from self.httpQuery("DELETE", path))